The prior art teaches that metallic screen structures (also termed cloths) are used in the rock aggregate business to size aggregate according to end use applications i.e. 1/4 inch, 3/4 inch, 1 inch, and smaller sizes. The screen structures are generally positioned in an incline below a conveyer belt crusher and must be formed from a hardened steel to sustain the pounding of the crushed material. However, since nothing lasts forever, certain areas of the screen develop breaks such that larger than desired aggregate fall through to contaminate the screened pile of material below the screen. Present practice is to use V-belt strips interwoven to block the broken grid to prevent contamination of the material below. This method is very time consuming.
The following is a list of the U.S. Pat. Nos. relating to this invention.
______________________________________ U.S. Pat. No. Inventor Date of Issue ______________________________________ 1,749,755 D. Downer March 11, 1930 1,998,033 F.E. Tucker April 16, 1935 1,927,826 R.W. Friday September 26, 1933 1,324,845 D. Osgood December 16, 1919 2,241,257 C. Gronberg May 6, 1941 2,272,196 S.R. Gittens February 10, 1942 2,283,803 S.R. Gittens May 19, 1942 2,487,830 C. Robbins, II November 15, 1949 2,190,993 H.H. Muir February 20, 1940 3,016,203 C.G. Sears, et al. January 9, 1962 ______________________________________
The above listed patents can be categorized into three groups, Group I including U.S. Pat. Nos. 2,190,993 and 3,016,203, pertaining to replaceable crusher screens and crusher systems. Group II includes U.S. Pat. Nos. 1,324,845, 2,272,196, 2,283,803, and 2,487,830, pertaining to screen repair devices where the ends of the repair screens are formed to effect a grip on the damaged screen. Group III includes U.S. Pat. Nos. 1,749,755, 1,998,033, 1,927,826, and 2,241,257 pertaining to screen repair devices where a clamping element has been added near the periphery of the patch to effect the interconnection to the damaged screen. Although the prior art teaches repair of screens in the window/door industry, see generally U.S. Pat. Nos. 2,272,196 and 2,283,803 to Gittens, pertaining to screen patches with hook formed ends, and although the prior art also teaches replacing a complete screen in a crusher system, see U.S. Pat. No. 2,190,993, none of the above listed prior art patents teach screen apparatus for repairing or modifying the extremely rigid type of screens used in rock crusher systems. In particular, the prior art does not teach a screen repair kit that includes a patch member having engagement structure adapted to endure rugged pounding action seen in a rock crusher environment. The Gittens patents, while teaching a hook engagement structure(s) for repairing screens, the hook engagement structure(s) taught does not adequately maintain the patch member in rigid locking engagement manner to keep the patch fixedly in-place over the ruptured portion of the primary screen. The patch member for aggregate screens should not be allowed to move and create a counter-productive situation in the main objective of producing a particular aggregate yield rate. It is believed that if the patch is allowed to move while in place over the screen rupture, the movement may not be in unison with the shaker movement of the primary screen, hence a non-uniform rate of aggregate screening may result. Further, while U.S. Pat. No. 2,190,993 teaches a gradation system with a plurality of gradation screens, the only structure contemplated for modifying the screen deck, for aggregate specification control or for damaged screens, is by replacing the entire screen, i.e. a costly inventory situation is created.
Thus, a need is seen to exist for an aggregate screen repair/modification kit that contains overlay portions of the same or smaller screen mesh structure having terminating ends formed for engaging to the main screen grid at the damaged screen area, or to the screen section to be modified.
A need is also seen to exist for an aggregate screen repair/modification kit that contains overlay portions of the same or smaller screen mesh structure having terminating ends formed for hooking to the primary screen at one end of the damaged mesh section, or screen section to be modified, and terminating ends at the other end formed to snap-fit (compression fit), or clamp to the damaged mesh section's other end.
A need is also seen to exist for an aggregate screen repair/modification kit that contains overlay portions of the same or smaller screen mesh structure having terminating ends formed having an impact point for effecting outward clamping securement to mesh elements associated with a damaged screen area, or a screen section to be modified.